Means for preventing condensation in refrigerator walls



May 3, 1932. D. F. KEITH 1,857,086

MEANS FOR PREVENTING QONDENSATION IN REFRIGERATOR WALLS Filed Nov. 20.1928 s SheetS -Sheet 2 .J Y L 30 a M 5 K J J -28 ,W a b R /0 a g moz PQMQRM May 3, 1932. D. F. KEITH 1,357,036

MEAP IS FOR PREVENTING CONDENSATION IN REFRIGERATOR WALLS Filed Nov. 20,1928 3 Sheets-Sheet 3 -caused also by changesin barometer pressure,

the atmospheric air is Patented May 3, 19 32 UNITED STATES PATENT.OFFICE.

DAVID E. KEITH, or crfivnrmn HEIGHTS, oHIo, AssIeNon 'ro rmrnc'rroxSTOVE comrm, or CLEVELAND, onto, a conronarron or 01:10

MEANS FOR PREVENTING COHDENSATION IN REFRIGERATOR .WALLSApplicatlonfiled November 20, 1928. Serial no. 920330.

This invention relates to means for preventing the condensation ofmoisture in the interior of the insulated walls of refrlgerationcabinets and it is applicable to all classes of refrigerators whereinthe cold chamber is enclosed by double walls consisting of spacedapartinner and outer sheets or panels of suit: able material between whichthere is a filling of insulation such as ground cork, balsam' wood, orthe like.

For the purpose of this descriptiomthe innor and outer sheets or panelsof a double wall construction will be referred to as the inner and outerwalls, and either may consist of a continuous shell, as will hereinafterappear.

a fresh supply of ice isplaced within the ice compartment; inrefrigeration apparatus of the intermittent absorption type, thesocalled cold chamber is of a higher temperature during the heating andcondensing period than it is during the period of evaporation andabsorption; and in other types of mechanical refrigerators, thetemperature of the cold chamber is higher during the defrostingoperation than at other times, and furthermore it fluctuatesconsiderably dueto the intermittent operation ofthe apparatus.

In the construction of double wall refrigerator cabinets, it ispractically impossible to make the space between the inner and outerwalls air tight, and as a consequence of this, when the temperaturewithin the cold cham-' ber rises, the air within the space between theinner and outer walls expands and some the air within the wallscontracts-and draws Obviously, this breathin atmospheric air.

ing action of the insulated walls may changes in outside temperature,etc. Since practically always In practically all types of refrigerators,there is a pronounced fluctuation of the tem more or less humid, themoisture which it contains 1s condensed when it comes within thechilling influence of the inner wall that.

separates the insulation space from the cold chamber and the insulationwithin said space absorbs the moisture untilfinally it becomes ,sosaturated that it has little insulting value.

In fact, when it becomes wet it is a conductor of heat between the innerand outer wall panels.

Attempts have been made to overcome this difficulty by hermeticallysealing the insulating material. Cork, for example, has been thoroughlycoated with a composition ofasphalt, as by dippin or painting the corkwith the compound. (Stber kinds of insulation have been wrapped in Waxedpaper. Both of these methods of moisture proofing the insulation arecostly and require a great deal of care in order to make certain thatevery openmg is sealed, for the-smallest opening in the protectivecoating will defeat the purpose thereof. By providing means forpreventing .the condensation of moisture in the interior of theinsulated walls of refrigerators,-much cheaper insulating materials maybe used with highly satisfactory .results.

The primary purpose of my invention is to provide a refrigerator cabinetenclosing the so-called cold chamber and constructed of double orspaced-apart inner and outer walls, the space between said wallscontaining suitable insulating material, and to incorporate in suchcabinet apassageway leading from the exterior tothe interior of saidspace and passing in intimate heat exchanging relation to a coolingmedium, such as the cold chamber, so that when the pressure differentialbetween the outer air;and the insulation space is in favor of the outerair, the atmospheric air drawn ingby reason thereof through saidpassageway is lowered in temperature below the temperature of said spaceso that any moisture in the air -that.would otherwise be condensed uponreaching the space is actually removed from the air by condensation inthe passageway.

Other objects of the invention are to provide means of the aforesaidcharacter that is simple, relatively inexpensive, highly efii cient,that requires no attention, and will not get out of order.

The invention is especially suited for refrigeration apparatus of theintermittent absorption type because of the fact that at regularmtervals in the operation of the apparatus, the temperature of the coldchamber or refrigeration compartment is raised above normal operatingtemperature for a brief pe riodwhile the relatively hot refrigerantcondensate is collecting in the evaporator. Each time this occurs, thewarmth of the-evaporator is communicated, to a limited degree at least,to the walls of the cold chamber or refrigeration compartment and thiscauses the air within the insulation space of the walls to expand and,as the cabinets have heretofore been constructed, a part of it to beexpelled through the small cracks or holes that are practicallyunavoidable, and then during the subsequent cooling period, when therefrigerant in the evaporator. is vaporizing and being distilled overinto the generator absorber the temperature of the cold chamber orrefrigeration compartment falls as does also the temperature of the airwithin the insulated walls causing said air to-contract and draw inatmospheric air. This breathing action occurs with every change oftemperature of the cold chamber.

Because of its peculiar adaptabilityito the class of apparatus justdescribed, Ihave illustrated my invention in connection therewith intheaccompanying drawings wherein Fig. 1

a5 is a sectional front elevation of refrigeration apparatusincorporating my present improvements, all parts excepting the cabinetbeing shown in elevation; Fig. 2 on-a somewhat larger scale, is avertical section through the cabinet from front to rear; Fig. 3 is asectional plan, the plane of section-being immediately below the top ofthe cabinet; Fig. 4 is a horizontal section through the breather tubeand the adjacent portion of the cabinet wall, the same being on a Scaleconsiderably enlarged over thatof the previous views, and Fig. 5 is asectional detail on the line 55 of Fig. 4.

The cabinet of the refrigerator is desig* nated 1 andit is made up of aframework comprising a base 2, top 3, rear corner posts 4 and frontcorner posts 5. An insulated door 6 swings between the last mentionedcorner posts and closes the cold chamber or refrigeration compartment 7that is formed by the interior of what is, in effect, a onepiece sheetmetal shell that constitutes the inner wall, of the cabinet and isdesignated 8. While this one-piece shell is in accordance with thebetter practice, the wall 8 might be made up of a number of separatepanels, so far as my present invention is concerned. Applied to thecorner posts 4 and 5 are sheets or panels of suitable material, such asmetal, and they constitute the outer wall that is constitutes thesubject matter of my co-pend-.

ing application Serial No. 242,574, filed December 27, 1927, and for adetailed description of the construction and operation of theapparatusreference may be had to the said case. It is suflicient for thepresent purpose to explain that during what is known as the heatingperiod of each cycle of operation, relatively hot refrigerant condensatecollects within the cooling unit or evaporator 12 and warms the samewhich results in a'noticeable rise in temperature of the air in thechamber or compartment 7 and, through the conductivity of the wall 8, ina warming up of the air within the space between said wall and the outerwall 9.

Following the heating period is what is known as thecooling period whenthe liquid refrigerant in the coolin vessel or evaporator 12 evaporatesand a stracts heat from the air within the chamber or compartment ,7,lowering the temperature thereof which is more or less variation in thetemperature of the cold chamber or refrigeration compartment.

In the present embodiment of my invention,

I employ a U-shaped breather tube 15 that.

is disposed immediately below the cooling unit or evaporator 12 andwhich has one of its ends extended through the rear sections of theinner and outer walls 8 and 9, and its other end projected through thewall 8 so as to open into the space between said walls. A cup-shapedscreen 16 surrounds the last mentioned end of the breather tube andprevents. the same from beingv closed or obstructed by the insulatingmaterial 10. The tube is inclined downwardly and forwardly so that itslowest part is adjacent the front of the chamber or compartment 7 saidlowest part constituting a sump, and a drip spout 17 is connected to thesump and dips into a receptacle 18 which provides a liquid seal for thespout. The receptacle 18 overflows into a pan 19 that is shown assupported by a shelf 20 sustained by and besaid pan serving also tocatch any c0n'densatewhich may drip from the cooling unit. It will bereadily understood from the foregoing description that when thebreathing action occurs within the space between the innor and outerwalls 8 and 9, air is alternately expelled and inhaled through thebreather tube 15, and such moisture in the air that is drawn in throughsaid tube as would otherwise be condensed in the space of the walliscondensed when subjected to the cooling influence of the unit orevaporator 12 and drains to the lowest point of the breather tube fromwhich it escapes through the drip spout 17 into the receptacle 18, saidreceptacle, in turn, overflowing into the pan 19, as .above explained.Thus it Willbe seen that no moisture can condense from the air thatfinds its way to the space between the walls 8 and 9 of the cabinetbecause the air has previously been subjected to a temperature lowerthan that which exists in said space, and consequently the insulatingmaterial 10 never becomes moist, but remains dry and retains its maximuminsulating value indefinitely;

The insulated door 6 closes the open front of the cabinet 1 and the sameis made up of a frame 26 to the inner and outer sides of which areapplied, respectively, the inner wall or panel 28 and the outer wallorpanel 29. The space between said walls-isfilled with insulatingmaterial 30, which, as in the case of the insulated walls of thecabinet, may be balsam wood.

To protect the insulation of the door from moisture I employ a breathertube 32 whose body portion is located on the inner side of the wall 28where it will be inside the cold chamber when the door is shut, and theupper endof the tube is extended through an aperture in said wall andopens into the insulation space, a screen 33 serving to space theinsulation-material from the open end of the tube. The opposite end ofthe tube is shown as extended through apertures in the inner and outerwalls28 and 29 so as to be open to the atmosphere; and it is, of course,understood that the apertures in the walls through which the ends of thetube pass aresealed against the ingress and egress of air. The outwardlyextended lower end of the breather tube 32 is preferably inclinedupwardly so as to pro vide a low part or sump 35 to which will gravitateany moisture condensed from. the atmospheric air as the latter passesupwardly through the tube in intimate heat exchang ing relation to thecold chamber of the' refrigerator. The sump 35. is drained through aspout 36 into a receptacle 37 which is-so related to thespout as toprovide a liquid seal therefor, and the receptacle overflows into areceiver38 that is shown as removably supported by the door so that itmay be conveniently emptied as occasion requlres.

The manner in which this breather tube functions will be obvious fromthe above descriptlon of the operation of the breather tube Acharacteristic of the breathing action of insulated refrigerator wallsthat is favorable to the present invention is that the exhalation occursduring the time the temperature of the cold chamber is rising and theinhalation takes placeafter the temperature of the cold chamber hasfallen enough to lower the-temperature in the insulation space of thewalls. Consequently, when the air is being drawn in through the breathertube the temperature of the walls of said tube-will be suflicientlybelow that of the insulation space to insure condensation of allmoisture in the existing in said space, said passageway being arrangedto drain any moisture condense therein away from said space.

y 2. A refrigerator comprising a cabinet having spaced-apart inner andouter walls and enclosing a cold chamber, the space between said wallscontaining insulating material, the cabinet incorporating apassagelation to the cold chamber, the samebeing so arranged as to drainany moisture condensed therein away from said space.

3. A refrigerator comprising a cabinet tweensaid walls containinginsulating material, the cabinet incorporating a passagea-ndpassing-in-intimate heat exchanging relation to the cold chamber, thesame involv- 'ing a sumpwherein any moisture that is con densed in thepassageway will collect.

4; A refrigerator comprising a cabinet and enclosing a cold chamber, thespace between said walls containing insulating material, the cabinetincorporating a passageway leading from its exterior to said space andpassing in intimate heat exchanging relationto the cold chamber, thesame involving a [sump vwherein an'y moisture that is condensed in thepassageway will collect, and means permitting the egress of condensateway-leading from its exterior tosaid space and passing in intimate heatexchanging rehaving spaced-apart inner and outer walls and enclosing acold chamber, the space be- .way leadingfrom its exterior to said spacehaving spaced-apart inner and outer walls from the sump and preventingthe ingress of air thereto from the cold chamber. 5. A refrigeratorcomprising a cab net I having spaced-apart inner and outer walls andenclosing a coldv chamber, the space between said Walls containinginsulating material, a conduit opening at one end ext-eriortween saidwalls containing insulating ma terial, a breather tube opening at oneend exteriorly of the cabinet and at its opposite end into said spaceand having a part located within said cold chamber, the tube being.inclined to drainany moisture that is condensed within it away fromsaid space.

7. A refrigerator comprisingacabinet having a spaced-apart inner andouter walls and enclosing a cold chamber, the space between said wallscontaining insulating material, a breather tube opening at one endexteriorly of the cabinet and'at its opposite end into said space andhaving a part located within said cold chamber, said part incorporatinga sump to which any moisture that is condensed within the tube drains,said sump being provided with an outlet.

8. A refrigerator comprising a cabinet having spaced-apart inner andouter walls and enclosing a cold chamber,- the space between said wallscontaining insulating material, a breather tube opening at one endexteriorly' of the cabinet and at its ,opposite end into said space andhaving a part located within said cold chamber, said part incorporatinga sump to which any moisture that is condensed within the tube drains,said sump being provided with an outlet, and a liquid seal for saidoutlet.

9. In a refrigerator, a cabinet having spaced-apart inner and outer wasand enclosing a cold chamber, insulating material in the space betweensaid walls, a cooling unit within said chamber, a breather consisting oftwo tubular branches that are communicatively connected togetheradjacent their inner ends and are disposed in intimate heat exchangingrelation to the cooling unit, the

outer end of one of said branches extending through the inner and outerwalls of the cabinet so as to open into the atmosphere while thecorresponding end of the other tube enters the space between said walls,the breather having a sump for. the accumulation of condensate, and adrain for said sump.

10. In 'a refrigerator, a cabinet having spaced-apart inner and outerwalls and enclosing a cold chamber, insulating material in the spacebetween said walls, a cooling unit within the cold chamber, a U- hapedbreath-j er tube disposed below said cooling unit and open into theatmosphere and its opposite end extended through the inner wall of thecabinet so as to open into the space contain ing the insulatingmaterial, the tube being inclined downwardly and inwardly and havingdraining means at its low point.

11. In a refrigerator, a cabinet having spaced-apart inner and outerwalls and enclosing a cold chamber, insulating material in the spacebetween said walls, a cooling unit within the cold chamber, a U- hapedbreather tube disposed below said cooling unit and having one of itsends extending through the inner and outer walls of the cabinet so as toopen into the atmosphere and its opposite cabinet so as to open into thespaceconta-ining end extended through the inner wall of the theinsulating material, the tube being inclined downwardly and inwardly andhaving.

a'drainopening at its low point, and a receptacle supported in receivingrelation to said drain opening and providing a liquid seal therefor.

12. In a refrigerator, a cabinet enclosing the cold chamber and having adoor opensulating material, the door incorporating a passageway leadingfrom its exterior to said space and passing in heat exchanging relationto the cold chamber, the same being so arranged as to drain any moisturecondensed therein away from said space.

13. In a refrigerator, a cabinet enclosing the cold chamber and having adoor opening, a door for closing said opening and comprisingspaced-apart inner and outer walls, the space between said wallscontaining insulating material, the door incorporating a passagewayleading from its exterior to said space and passing in intimate heatexchanging relation to the cold chamber, the passageway involving a sumpwherein any moisture that is condensed in the passageway will col-'lect, and means for draining thesump.

14. In a refrigerator, a cabinet enclosing the cold chamber and having adoor opening, a door for closing said opening and comprisingspaced-apart inner and outer walls, the space between said wallscontaining insulating material, the door incorporating a passagewayleading from its exterior to said space and passing in intimate heatexchanging relation to the cold chamber, the said passageway involving asump wherein any moisture that is condensed in the passageway willcollect, and a liquid seal through which said sump is drained.

15.. In a refrigerator, a cabinet enclosing the cold chamber and havinga door opening, a door for closing said opening and comprisingspaced-apart inner and outer walls,

insulating material in the space-between said walls tion disposedinwardly of the inner wall and having one of its ends extending throughboth inner and outer walls so as to be open to the atmosphere, the otherend of said tube V opening into the space between the walls, the

tube being so arranged as to drain any moisture condensed therein awayfrom said space.

16. In a refrigerator, a cabinet enclosing a cold chamber and having adoor opening,

a door for closing said opening and com rising spaced-apart inner andouter walls, insulating material in 'the space between said Walls, abreather tube having its body portion disposed inwardly of the innerwall and having one of its ends extended through the inner and outerwalls so as to be open to the atmosphere, the opposite end of the-tubeopeninginto the space between said walls, the tube being so formed as toprovide a sump, a drain spout for said sump which discharges on theinner side of the door, and a vessel into which said spout drains. 1

' 17, In a refrigerator, a cabinet enclosing a cold chamber and having adoor opening, a door for closing said opening and comprisingspaced-apart inner and outer walls, insulating material in the spacebetween said walls, a. breather tube-having its body por tion disposedinwardly of the inner wall and having one of its ends extended throughthe inner and outer walls so as atmosphere, opening into the spacebetweensaid walls, the tube being so formed as to provide a sump, adrain spout for said sump whichdischarges on the inner side of the door,a recepto be open to the tacle so disposedwith respect to said spout asto provide a liquid seal therefor, and a reinto ceiver removablysupported by the door which said receptacle overflows.

In testimony whereof, I hereunto afiix my signature.

DAVID F. KEITH.

a breather tube having its body'por-.

the opposite end of the tube

